1. Field of the Invention
This invention relates to KVM (keyboard video mouse) switches, and in particular, it relates to a KVM switch with internal USB hubs that can be connected to computers with a reduced number of cables.
2. Description of the Related Art
KVM (keyboard video mouse) switches are devices that allow one user console to be connected to and communicate with multiple computers. In a typical KVM configuration, one or more consoles and a plurality of computers (such as PCs) are connected to a KVM switch, and each console can selectively communicate with any one of the computers. Each console includes a plurality of user interface devices such as a keyboard, a mouse, a monitor, a microphone and a speaker. In some conventional KVM switches, shown in FIG. 1, each user interface device of the console is connected to the KVM 100 switch by a separate cable. Thus, as shown in FIG. 1, the user console is connected to the KVM switch by a VGA (video) cable C1 for the monitor, a cable C2 for the speaker, a cable C3 for the microphone, a cable C4 for the keyboard, and a cable C5 for the mouse. The keyboard and mouse cables are USB cables in this example. Likewise, each computer (PC) is connected to the KVM switch by multiple cables to transmit various signals. As shown in FIG. 1, the first computer PC1 is connected to the KVM switch by a VGA (video) cable A1 for the monitor signals, a cable A2 for the speaker signals, a cable A3 for the microphone signals, a cable A4 for the keyboard signals, and a cable A5 for the mouse signals. The keyboard and mouse cables are USB cables in this example. The second computer PC2 is similarly connected to the KVM switch. It can be seen that a large number of cables are used, making it inconvenient to manage. Although FIG. 1 schematically shows one switch 101, various signals may be switched separately within the KVM switch. For example, the keyboard/mouse signals (which are digital signals) are typically switched separately from the video signals (which are analog signals).
In the conventional configuration shown in FIG. 1, in addition to a large number of cables connecting the computers with the KVM switch, another disadvantage is that the audio signals (speaker signals and microphone signals) are transmitted between the computers and the KVM switch by analog cables. Such cables often cause distortions in audio signals.